In connection with the use of a variety of diagnostic apparati such as X-ray projection, NMR (nuclear magnetic resonance), and other diagnostic systems there often arises the need to focus the diagnosis on a single organ or other limited area of a patient and to conduct the diagnosis from a variety of angles without moving the diagnostic apparatus. Table apparati are typically used but suffer from various disadvantages including interference of the table apparatus with access to the patient, complexity of operation of the table and inconsistency in maintaining the localized area of the patient to be examined within the diagnostic beam or other focus of the diagnostic apparatus.
SUMMARY OF THE INVENTION
In accordance with the invention there is provided an apparatus for tilting a patient supported on a diagnostic table and simultaneously maintaining a selected isocenter of the patient at a selected fixed point in space comprising a table for supporting the patient within an examination zone of a diagnostic apparatus; a vertical carriage mechanism connected to an end of the table for raising and lowering the end of the table through a predetermined range of vertical travel; a tilt pivot connecting the end of the table and tilting the table through an arc of at least about 10 degrees; a horizontal leg mechanism movably mounted to the vertical carriage mechanism for moving the vertical carriage mechanism and the table through a predetermined range of horizontal travel; the vertical carriage mechanism being movably mounted on the horizontal leg mechanism; the horizontal leg mechanism being movably mounted on an overhead arm mechanism; wherein the vertical carriage mechanism is movable along a vertical travel and the horizontal leg mechanism is movable along a horizontal travel sufficient to maintain the isocenter of the patient at the fixed point in space when the table is tilted around the tilt pivot.
Preferably the apparatus includes a mechanism for rotating the arm mechanism, the vertical carriage mechanism, the horizontal leg mechanism, and the table around an axis intersecting the selected isocenter of the patient. The mechanism for rotating is typically connected to the overhead arm mechanism.
Preferably the apparatus includes a mechanism for automatically moving the vertical carriage mechanism and horizontal leg mechanism along vertical and horizontal displacement sufficient to compensate for the vertical and horizontal displacement of the isocenter away from the fixed point in space when the table is tilted about the tilt pivot; and, most preferably the mechanism for automatically moving includes a mechanism for simultaneously driving the vertical carriage mechanism and horizontal leg mechanism along vertical and horizontal displacements sufficient to compensate for the vertical and horizontal displacement of the isocenter away from the fixed point when the table is tilted about the tilt pivot.
Typically, the mechanism for driving includes a mechanism for directing the vertical displacement of the vertical carriage mechanism by a distance x in response to a change of an angle A in tilt of the table relative to horizontal according to the formula: X=L sin A, where L is the approximate straight distance between the tilt pivot and the center of the selected isocenter; and a mechanism for directing the horizontal displacement of the horizontal leg means a distance Y in response to the change of angle A according to the formula: Y=L-(L cos A).
Most preferably the apparatus further comprises an expandable and contractable strut mechanism a selected degree; a mechanism for measuring the change of angle A of the table when the strut mechanism is expanded or contracted; and, a mechanism for inputting the change of angle A into the formulae X=L sin A and Y=L-L cos A of the mechanism for driving.
Typically the leg mechanism is slidably mounted on a first track mechanism included on the underside of the arm mechanism and the carriage mechanism is slidably mounted on a second track mechanism included on the leg mechanism, the mechanism for driving further including a first motor mechanism connected to the leg mechanism, and the leg mechanism for directing the horizontal displacement of the leg mechanism and a second motor mechanism connected to the carriage mechanism.
The leg mechanism typically includes a first roller mechanism mounted in the first track mechanism, the first roller mechanism being connected to and driven by the first motor mechanism, and the carriage mechanism typically includes a second roller mechanism mounted in the second track mechanism, the second roller mechanism being connected to and driven by the second motor mechanism. Most preferably, the mechanism for directing the vertical displacement of the vertical carriage mechanism, directs the driving by a distance X in response to a change of an angle A in tilt of the table relative to horizontal according to the formula: X=(L sin A)+(V sin A tan A/2); where L is the approximate straight distance between the tilt pivot and the center of the selected isocenter and V is the shortest distance between the center of the selected isocenter and the surface of the table; and, most preferably, the mechanism for directing the horizontal displacement of the horizontal leg mechanism, directs the driving by a distance Y in response to the change of angle A according to the formula: Y=L-( L cos A)+(V sin A).
The apparatus typically further comprises an expandable and contractable strut mechanism pivotably connected to the vertical carriage mechanism and the table, a mechanism for expanding and contracting the strut mechanism a selected degree, a mechanism for measuring the change of angle A of the table when the strut mechanism is expanded or contracted, and, a mechanism for inputting the change of angle A into the formulae X=(L sin A)+(V sin A tan A/2) and Y=L-(L cos A)+(V sin A) of the mechanism for driving.
The mechanism for measuring typically comprises a mechanism connected to the mechanism for expanding and contracting for converting the selected degree of expansion and contraction into the change of angle A.